1. Field of Invention
The present invention relates in general to transducers for converting pressure energy signals such as acoustic signals to electromagnetic energy signals as represented by light energy in order to take advantage of the avoidance of electrical power to effect the conversion.
2. The Prior Art
During the past several years considerable effort has gone into the development of optical sensors compatible with the present fiber-optics communications technology. In particular sensors that do not require power to convert acoustic signals into corresponding optical modulation are deemed highly desirable from the standpoint of reliability.
The development effort is evidenced by a modulator described in U.S. Pat. No. 4,086,484 to Steensma. There the modulator comprises an optical fiber clamped to a piezoelectric crystal. Acoustic signals interact with the fiber to change its index of refraction. As a result light is scattered out of the fiber and the beam of light attenuated as a function of the acoustic wave.
U.S. Pat. No. 4,142,774 to Wright proposes a transducer comprising an optical waveguide. Flexure of the transducer introduces strain patterns in the waveguide to produce diffraction and vary the characteristics of the light transmitted through the waveguide. In one embodiment the transducer is coupled at opposite ends to optical fibers.